Fed-BioMed module imports takes almost 5s

[srcansiz]

Launching node components takes more than 5 seconds. Same behavior can be encountered on the researcher notebook while importing classes such as Experiment or request for the first time.

After investing the performance using python profiler, I've realized that it is due to time that is consumed during the module imports. For example, importing modules in node/cli.py module takes almost 5s each time node CLI is called. Since fedbiomed_run executes node.cli at least two times (one for configuration generation second for launching the node ), starting a node almost take 8-9 seconds.

Please see result for the import section in fedbiomed.node.cli:

After the first inspection, I realized it is probably due to environ object that is imported almost every module in Fed-BioMed. This can be a bug or an implementation choice depending on the reason behind the time consumed. However, it needs to be investigated and clarified.